Mendel’s principles apply to humans. A pedigree is a family tree that records and traces the occurrence of a trait in a family. Example: Free or Attached Earlobes Pedigrees figure out more serious matters when the alleles in question cause disabling or lethal disorders.

What is a Carrier? A carrier is an individual who has one copy of the allele for a recessive disorder and does not exhibit symptoms.

Predicting and Treating Genetic Disorders A genetic counselor is trained to collect and analyze data about inheritance patterns and to explain the results and their significance. Examines the families history Perform Tests Baby is born, perform certain test to detect chromosomal and genetic disorders in the fetus. Other tests analyze the fluid surrounding the fetus to detect chemical imbalances that point to specific disorders.

12.4 Growth Factors-initiate cell division and produce proteins Cancer Genes Growth Factors-initiate cell division and produce proteins Tumor-Suppressor Genes-produce proteins that stop cell division in particular situations-for example, when cells contain damaged DNA Oncogene-cancer-causing gene

FF or Ff = Free ff = attached Don’t be concerned if they find that two parents with attached earlobes have a child with free earlobes. Human traits often do not completely follow Menedlian inheritance. Other genes and environmental factors may also influence earlobe appearance. If a person is homozygous recessive most likely cannot have a biological parent who is homozygous dominant ( or vice versa)